Row occurrence counting algorithm

Question

I am curious what the most efficient algorithm (or is usually used) for counting the number of occurrences of a string in a piece of text.

From what I read , Boyer-Moore's string search algorithm is the standard for finding strings, but I'm not sure if counting the occurrences in an efficient way will be the same as finding a string.

In Python, this is what I want:

text_chunck = "one two three four one five six one"
occurance_count(text_chunck, "one") # gives 3.

EDIT: It seems that python str.countserves as such a method; however, I cannot find which algorithm it uses.

Answer 1

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Answer 2

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Answer 3

Hellnar, String. , :

"""
The counting algorithm is used to count the occurences of a character
in a string. This allows you to compare anagrams and strings themselves.
ex. animal, lamina a=2,n=1,i=1,m=1
"""

def count_occurences(str):
  occurences = {}
  for char in str:
    if char in occurences:
      occurences[char] = occurences[char] + 1
    else:
      occurences[char] = 1
  return occurences

  def is_matched(s1,s2):
    matched = True
    s1_count_table = count_occurences(s1)

    for char in s2:
      if char in s1_count_table and s1_count_table[char]>0:
      s1_count_table[char] -= 1
    else:
      matched = False
      break
    return matched

  #counting.is_matched("animal","laminar")

This example returns True or False if the strings match. Keep in mind that this algorithm counts the number of times a character appears in a string, this is useful for anagrams.